Learning performance of honey bees after antennal contact plus oral ingestion of 12 ng imidacloprid.

<p>Imidacloprid was fed to bees 5 minutes prior to the first acquisition trial (AT1). Control bees were fed sucrose solution only. Percent conditioned response refers to the percentage of bees in each group that gave positive responses at each trial. Number of subjects in each group is indicated in parentheses. *<i>P</i><0.05 (Fisher’s exact test) relative to the aggregate control.